Closure operator



1 8 1932- J. T. CONWAY 1,874,903

,CLOSURE OPERATOR Filed Dec. 26, 19%8 3 Sheets-Sheet l AL ATTORNEY a WMW Aug. 30, 1932. J CQNWAY 1,874,903

CLOSURE OPERATOR Filed Dec. as, 1928 3Sheets-Sheef 2 J. T. CONWAY Aug.30,1932.

CLOSURE OPERATOR Filed Dec. 26, 1928 3 Sheets-Sheet 3 HUM " ATTORNEYPatented Aug. 30, 1932 UNITED Y STATES JOSEPH T. CONWAY, OF QLEVEIQAND,OHIO onos URE OPERATOR Application filed December 26 1928; Serial No.328,450.

My invention-is an improvement'in closure operating mechanism andrelates more particularly to means for opening closures such as enginehouse and garage doors and then automatically closing the same upon theexpiration of a predetermined period of time.

One of the objects of my invention is to open and then automaticallyclose doors or other closures at the expiration of a predeterminedperiod of time. TI

Another object of my invention consists in providing power operatedmeans for opening and closing doors but permitting manual operationthereof withoutinterference from the power operated means.

or premature closing of the doorsas the result of external forcessuch aswind.

Another object of my invention is to give ample warning to passersbythat the doors are being opened and that a vehicle is about to leave thebuilding.

Another object is to automatically release trap doors such as are usedin fire engine houses communicating one floor of the building withanother, almost simultaneously with the energization of the motorcircuit.

' Another object of the invention isto simultaneously sound alarms,release traps and open the doors, when the invention is applied to fireengine stations, the said alarms being 'de-energized before the doorsare automatically closed.

Further objects and advantages of my infollowing description of anembodiment thereof progresses reference being made to the accompanyingdrawings inwhich like reference characters are employed to designatelike parts throughout the same.

Figure 1 is a diagrammatic view of the electrical circuit employed inconnection with my invention showing certain of the parts in dotted andfull line positions. r

Figure 2 is a bottom plan view of one embodiment of my invention shownin useas applied to doors swinging about a vertical axis and showingtheextreme positions of some of the parts of the apparatus when the doorsare in closed or open position.

A further object is to prevent accidental vention will become moreapparent as the Figure 3 is a side elevation of a portion of anapparatus embodied in my invention in which the cover plate of aswitchbox ha's'been removed. V I.

Figure 4. is an' enlarged fragmentaryview of a portion of the trackshowing 'theicarriage in one of its limits of movement along the track.I i I Figure 5 is an enlarged fragmentary view of another fragmentarysection vof thetrack representing the forward end of the track'andshowing the manner of supporting the means for moving the carriage alongthe track.

Figure 6 is an enlarged sectional view taken on line 6 6 =of Figure3. c

Figure 7 is a sectional view taken on line 77' of Figure 5. p 3

Figure 8 is an elevational view of the cylinder movable with thecarriage showing the by-pass connect-ion forvthe cylinder.

Figure 9 is an enlarged section taken on line 99of Figure 3. a

Figure 10 is an enlarged section taken on line 10'10 of Figure 3. i i-Figure 11 is an enlarged elevation of a part of my invention includingmeans for locking the doors in open positions andv against accidentalclosure.

Figure 12 is a section taken on line of Figure 11. l

In the accompanying drawings illustrating one embodiment of my inventionand referring more particularly to Figures 2 'to' 8 inclusive, 1represents a frame for doors or other closures 2, which in the presentembodi ment'are mounted to move about a vertical axls. I have providedmeans for moving the doors about their'respective axes, which in thepresent embodiment I have illustrated as including connecting rods 3pivotally "connected at one of their ends to the doors, as at 4, andpivotally connected at their other V respective ends 5 to the carriage6.1 The carriage is movable along a track or other sup- 5 port 7, and inFigure 2 I have illustrated theposition of the carriage and connectingrods in full lines, indicating their position when the doors are closed,while in dotted lines I have illustrated these partsiin their 0respective positions when the doors are open. Referring moreparticularly to Figures 4, 5, 6 and 7 it will be seen that the track0011'- sists of a substantially inverted U-shape housing is providedwith a rearwardlyv extending shoulder 13 to which the supporting rod 11is attached. A depending stop or abutment 14 is'also formed on thehousing and is disposed in the path. of movement of the carriage forpurposes which will be described more fully hereinafter. The forward endof the casing 9 is supported within a housing or casting 15 whichterminatesin a bracket 10, by means of which it is support- ,ed on thedoor frame 1.

The carriage 6 consists preferably of a casting having connecting rodsupports 16 on opposite sides thereof, by means of which the ends of therods may be pivotally connected through the bolts 17. A cylinder 18is'preferably formed integrally in the carriage body and itslongitudinal axis extends substantially parallel to that of thetrack,although the cylinder may be separately formed and conveniently securedin position in'the carriage body if desired. The carriage is suspendedfrom the track by the rollers 19, which are freely rotatable aboutshafts which extend through the portion 20 of the carriage body. In theparticular embodiment illustrated herein, I prefer to employ rollershaving rubber tires,in order to minimize noise in operation such aswould bemanifcsted where there is metal to metal contact between rollersand the tracks. noted that the rollers travel along the flat portions 21of the spaced tracks formed in the channel 8.

A piston 22 provided with suitable packing is mounted to reciprocatewithin the cylinder .18 and is secured by means of a set screw 23 to therod 24 which is slidable through openings in the ends of the cylinder18. I have provided bonnets 25 which are detachably screwed upon eachend of the cylinder for slidably supporting the rod 24 therein: Thesebonnets may also be provided with packing means as at 26. Referring moreparticularly now to Figure 8, it will be seen that I have provided aby-pass consisting of a restricted conduit 27 communicating with theinterior of the cylinder 18 adjacent each end thereof. I have pro videda control valve 28 in the conduit for regulating the flow of oil orother fluid through the conduit from one end of the cylinder to theother, when the piston 22 is shifted from one end of the cylinder to Itwill be the other. In this manner the carriage may be brought to restagainst the desired cushion at either of its extreme positions along thetrack after the motor has been de-energized by the automatic opening ofthe respective reversing switches.

I have also provided means for moving the carriage 6 from either one ofits extreme positions to the other, which includes a belt or chain 30having its respective ends secured. to the turn buckles 31 and 32, whichare in turn secured to the portion 20 of the carriage. These turnbuckles permit the taking up of slack in the belt or chain from time totime. This is clearly shown in Figure 4. The chain passes over idlersprockets 33 and 34, which are rotatably mounted at the forward, andrearward ends respectively of the track 8; the lower portion of thechain extends through the channel 8 while the upper portion of the chainpasses over the sprocket 33, the driving sprocket 35 and under the idlersprocket 36 and over the intermediate idler sprocket 37 and about therear idler sprocket 34. The upper portion of the chain passes throughthe casing 9. The driving sprocket 35 is keyed to a shaft 38 to whichalso is keyed a reducing gear 39. The motor M is supported on thecasting 15 as shown in Figure I 3, and carries on its shaft 40 a gear 41which meshes with the reducing gear 39. The shaft 40 of the motorextends into a casing 42 which is formed integral with the casting 15,which houses the gears 39 and 41' and the forward end of the track. Aconduit 43 leads from the motor to the interior of the switch box 44,which is formed as a part of the casting 15 and carries thereinelectrical conductors 108, 110, 112, 113, between the posts of the motorand certain of the elec-' consist of the links 131 and 132 pivotallyconnected to the respective reversing switches at their outer ends andalso pivotally connected to the rod 130. The rod 130 extendssubstantially parallel along one side of the track and casing 9, and isprovided with adjustable lugs or stops 44 and 45 which may be adjustedto the desired positions along the rod 130. The rod 130 is movableaxially in suitable bearings to engage oneof the reversing switches withits respective contacts and to disengage the other reversing switch fromits respective contacts and rod 46 is supported along the track andextends substantially parallel to the rod 130. The rod 46 carriesthereon adjustable depending arms 47 and 48 which are capable ofswinging about horizontal axes 49. These arms may be adjusted by meansof set screws, to swing from the rod 46 at any desired point thereon,which may be selected bythe operator. In

the position of the parts shown in Figure?) with the carriage totheextreme right; it will be noted thatthe arm 48 is engaged byrthecarriage in its movement to the right and "in turn engages the stop va5secured to-rod 130.

In this :manner continued movementof the carriage will move, th'erod 130to itslimit of movement to the right, closingthe reversing switch RS andopening-the reversing switch RS \Vhen the carriage travels towards theleft along thetrack it will engage the depending arm 17 which inturnengages the stop irsecuredto the rod 130.

Continued movement of the carriage to the left will cause the rod130tobe mo vedto' the left, closing the reversing switch RS and opening thereversing switch RS. v

The intermediate sprocket 37 is rotatably supported at a pointsubstantially midway betweenthe sprockets 33 and 3e and serves tosupport the chain 30 at this point during its travel betweenvthe-sprocket 36 and the sprocket 34. The sp'rocket'37 is mounted in acasting50 which is provided with shoulders 51for supporting the ends ofthe casing section 9. This is shown in detail in Figure .5.

closures, and I have also'illustrated inTthisfigure the electrical"circuits used in connection with this apparatus. I will-now proceed todescribe these circuits.- L and L indicate a source of electrical energyand F indicates protecting fuses'in each side of the line. Forconvenience of description L 'may be designated as the side ofthe linecommon to all the electrically connected devices; I L is connectedthrough a'conductor L and snap switch A to the manually operatedswitches B and C. The switches 13 and G are of the normally open or pushbutton type; since it is only necessary to closeone of the switchesmomentarily to energize one of the respective solenoids S and Sdepressed, current will flow from L through the normally closed switchA; the switch .13 and conductor through the solenoid S and conductor Lpart of the currentpassing along the conductor 101, the solenoid S andthe conductors 103 and L The solenoid S actuates the plunger P, whenenergized, to

lift the latch L on the doors2 throughthe lever L and rod R ThesolenoidsS and S are energized simultaneously.

I of the switch. In this manner a motor When the switchB is noid'Sfl'theconductors 105and L ,-..energizing the solenoid S The plunger P i of thesolenoid S ris connected :to actuate a trip or latch L forreleasingthetrap doors T fiand T An audible alarmrA and .a light A are connectedacross {thelines 104 :and 105. When the doors i2 are closed thereversing switches RS and-RS and the plungerl i and automatic switchblades are in the dotted line positions indicated in Fig.1, before.the'push button switch B isficlosed. "Upon closing the switch Bmomentarily electric current will energize the solenoid S drawingtheplunger P to the right in the figure, engaging the automatic switchblades B B B?"andB with-the respective contacts C 0 51C? and C? anddisengaging the blades B B2B? and B? from the respective contacts G C Cand G is established as-follows I 1 Part of the current passing throughthe switch A passes along the wires 1'06 and 107 circuit a tothe bladesB and B wwhich are 'now in a contact with the contacts C and C of the"automatic switch": :From the 'contact C -a wire 108 carries the currentfromx'L topost M of the motor M, and from the contact (1 a wire 109 alsocarries the current from L and wire 107 to the blade B of the reversingswitch RS. A wire 1:10,1eads from the contact engaged' by B? tof-post M1 1?- the motor. FL? is therefore connected to. posts M and M? of themotor during thisphase'of theioperation of:the apparatus. 3:

' A wire 111 leads from thecontact blade B which is connected to-IE,toblade B of the reversingswitch RS- A connec= tionis thus made from Lithrough the blade B and a Wire 1152 to post M .of the motor M.Anothericonnection is made froin L through the blade B contact C andwire' 1- 13 to-post It will also'be noted that the siren A and 3.

street-light A will be energized immediately upon the engagement of theblade Br with the contact C which completesithe alarm' circuitand warnspassersby'that the doors are passing from L throughtheswitch Af and wire106 will continue through lthe wire 114 and thenormally closed contactsC and C of the switch I), to the siren A? and'light A beingopened.I'Theial'arm circuit just referred to maybe traced as'follows?Currentthrough the wire1 15. 1 A "wir e'116 connects I throughthe'contact O and blade B to L completing the'al'arm circuit; Thedevices A and A? will continue to be energizedfias long a's the'doors2remainopen and the blade B l engages Ic-ontact Cfiiand as long as theswitch arm D lengagesthe contact C Ihave providedmeans for automaticallyenergizing the solenoid S after a predetermined period a of time haselapsed since'the 2. is therefore connected to a energization of thesolenoid Sand I have also provided-manually controlled means forenerg-iz'ing the solenoids at will, the latter constituting more ofv anauxiliary means to be I through coil R, which is of relatively lowresistanceandthence through coil R whichis of relatively highresistance. i

The two coils are connected in series by the. wire 118, the wire119leading from the coil R and connecting to vL through the wiresl19 and111 and blade B? of the auto.- matic switch. The coil R extends axiallywithin a thermally responsive element T. This element consistspreferably of a spirally wound metallic strip anchored at its lower end120 in a suitable supportand carrying an outwardly extending arm 121 atits upper'end. The arm 121 terminates in an insulated head 122 whichnormally abuts an adjusting screw 123 in the circuit maker and breaker'D. Thus'it will be seen that as the coil R heats up, the spiralthermostatic element T will respond to the rise in tempera ture byexpanding spirally,, whereupon the arm 121 carried-bythe element andabutting the adjusting screw 123 carriedby the switch arm D will movethe hinged switch arm toward the observer, (Fig. 1) breakingthe contactsthrough C 'which' is behind the arm 121 and the switch arm D. As theswitch arm continues to movetoward the observer by continued spiralexpansion of the thermostat T it will contact with the contact C feedingcurrent from L through the wires 106 and 11 1 and switch arm D and wire124 to the solenoid S The solenoid S is, con nected to the wire Lthrough the wire 128 to complete the circuit. It will be seen that themovement of the switch arm, which is normally held against the contact 0b a spring 126 toward the contact C rst breaks the circuit through thesiren A and lamp A and then. completes the circuit through the contact Cto energize the solenoid S and pull the plunger P to the left in thefigure. When the plunger moves to the left the blades B B B and B aredisengaged simultaneously from the respective contacts C C C and C ofthe automatic switch, while the blades B B, B and B are .engaged withthe respective contacts C C, C and C As the doors approach the limit ofmovement representing their open. position, the rod 130 is moved to theleft in Figure 1 by means which havebeen described hereinbefore. One endof this rod is connected by links 131 and 132v to the reversing switchesRS and RS respectively, and movement of the rod tothe left will engagethe blades B and B with the contacts G and C and G V respectively andwill disengage. the blades B? and 13 from the .contacts G and Crespectively. .I haverepresented these positions of the reversingswitches, rod and links by-dottedlines in the figure.

' Itv will be noted that when thesolenoids S is energized vbythe closingofthe circuit through the switch D and contact C, the blades of theautomatic switch are moved to the positions shownv by dotted lines andthe heater circuit through wires 119, 111 and contact C is broken.However the return v of'the switch arm D to its normal position to closethe contacts D and C is retarded by thecooling'of the coil R and thecontraction of the thermostat T. In this manner the automatic-circuitthrough the solenoid S is of short duration. With the switch blades B B,B and B incontact with the respective contacts G G", C and C and thereversing switches RS and BS in the dotted line position, a motorcircuit is established for rotating the motorv armature in a reversedlrection to that when the doors are being opened. This circuit may betraced as fol lowsCurrent from. L flows through the wire 106, blade Band wire. 108 to post M of the'motor. Current also flows from L andwires106 and 107 through blade 13",

wires 133 and. 113 to post M of the motor. 7

Post M of the motor is connected to side L doors, whilewithautomatic'switch in the 1 position shown in full lines, posts M andM are connected to L and posts M and M are connected to L -With theautomatic switch in the dotted line position the motor is actuated toclose the doors by means which have been described. As thedoors'approach theclosed position the rod .130 is shifted. to therightinFigure 1, whereupon the reversing switches RS and RS will againassume the full lineposition and the motor circuit will be automaticallybroken. f

When the reversing switches RS and RS are in the dotted line positionacircuit is completed to operate a latch or look L which holds the doorsin open position and against accidental or premature closure by wind orother forces. This circuit remains closed only to unlock thelatchwhilethe automatic and reversing switches are in the dotted lineposition and while the motor is operating the contact C The switch RSbeing in closed A conductor 128 connects the other lead of position, thecurrent passes along the wire 135 and blade B to L A plunger P arrangedto operate the latch operates within. the solenoid S when the latter isenergized.

I have shown the means for operating the latch L in Figures 11 and12,-whicl1 includes a bell crank 60 operable by the plunger P to liftthe latch L through the connecting link 61. The hooked end of the latchengages one or more stops 62 on one of the connecting rods 3. When thedoors are opened the rod 3 moves to the left in Figures 11 and '12, thehookedend of the latch riding up the inclined walls 63 and over thestops 62 providing a positive lock to retain the doors in open position.When the doors are to be closed, however, and the solenoid Sis'energized, the latch will be lifted out of the path of movement ofthe rod 3 to the right.

I have provided a manually controlled electrical circuit for energizingthe solenoid '8? when it is desired to close the doors before thethermostat T has had time to move the switch D into contact with thecontact C. This circuit includes a push button .switch 0 connected onone side to L and on the other side by means of a wire 138450 thesolenoid S the solenoid to L of the line.

The switch Amay be. opened any time to disconnect the power line. Thusthe doors may be maintained in either an open or closed position atwill. r a i I will now describe the operation of my invention asillustrated in the accompanying drawings.

Assuming" that the doors 2 are'closed and that the various parts ofmyinvention are in the full line position of Fig. 2, in order, to open thedoors, the operator depresses the push button switch B of Fig. 1 to thefull line position, energizing the-solenoids S, S

and S The plunger Bis thus actuated'to release a latch L whichnormallyretains the doors in closed position. This latch is illustratedinFig..l. v p

The plunger P is likewise actuated upon: the energization of thesolenoid S to release a'latchL which has previously been positioned toretain the spring actuated trap visible signals A and A are energized toindicate the doors are open andtoilluminate Their movement may beretarded the area around the trap doors'to prevent accidents. v

When the solenoid S energized, the plunger P is shifted to the rightasshown.

in Figs. 1 and'10, closing the switch blades B B B and B withtheir.respective ,con-

tacts (1 ,020 and G In'this manner the motor M is energized to run in adirection for rotating the reduction gear 39 and vpinion 35(Fig. :5) inaclock-wise' directions-Theupper portion of the chain 30 is thus movedto. the right in Figs. 4 and5, while the lower portion moves toward theleft, drawing the;

carriage along the track, and. opening the 3 doors 2; In Fig. 2 I haveillustrated the carrlage in dotted lines in its limit of move-' ment tothe left to open the doors.

\ Referring now more particularlyto Fig. 3

it will be seen that, as thecarrige approaches" its limit of'movement tothe left in opening the doors, a portion16 of the carriage body w1llengagethe depending arm 47 which is freely movable about its pivot.Continued 'moveme'nt of the carriage to the left will cause this armtoengage the stop 44' secured.

to the slide bar or rod 130 and move the stop and rod 'to'the left-asufficient distance to disengagethe reversing switch RSfrom'its-contacts C and C and toengage the reversing I switch RS withits contacts G G 5 and C 4 before the carriage comes to rest." Referringto Fig. 1 it will be seen that opening of the swithRSwilldisrupt themotor circuit-and stop the motor, thus stopping the" movement 1 ofthecarriage substantially instantaneously with the'opening of the switchRS. 1

"It ishould also be noted that when the i plunger P is shifted to theright,1an alarm andiy'light circuit is closed through the wires 106 and114, switch contact" C and D con-.

tact C and. wire 115 to the streetlightAtand the siren A the circuitbeing completed I l through: the wire 116, contact 0 a switch: blade Band wire L alarm is given during the opening of the doors 2 to warnpassersby that the doors are opening or are opened anda vehicle isabout.

to pass therebetween.- The audible alarm and. light A? will continuetofunction as long as the switch arm D remains in contactwith the contact(3 I Q I A circuit isalso .establishedthrough the Thus an audible streetregulator and heater COllSR and R when'the plunger P is in the positionshown in Fig.1.-

This circuit is traced as follows-from L and switch A, wires 106, 114and 117 through the coil R of relatively low resistance,'wire 118- andcoil R of relatively highresistance, wires 119 and 111, and switch blade.B to L Therefore when the blade B engages its conlylow resistance, wire118and coil R of rel-' atively high resistance, wires 110 and'lll,

and switch blade Btto L Therefore, when r tact C currentwill passthrough thelrelativecuit.

will pass through the relatively low resist ance current regulating coilR. The current that passes through this coil is conducted through thewire to the heater coil R of relatively high resistance. The coil R is123 may be adjusted toward or away from the disc 122 to determine thetime interval between the energization of the coil R and the closing ofthe contacts D and C and also between the energization of the coil andthe breaking of the contact C of the alarm cir- Thus if it is desiredthat the de-energization of the alarm and the closing of the contacts Dand G be retarded, the set screw 123'may be adjusted away from the disc122 when 'thecoil R is cold, although it is obvious that by adjustingthe set screw closer to the disc 122 the elapsed time between theeneigization of the coil R and the beginning of movement of the switch Dabout its axis will be correspondingly shortened. By this means theenergization of the solenoid S and the de-energization of the streetalarm A V and light A maybe predetermined over desirable periods suchas, for example, from fifteen'seconds to two or three minutes after "ftthe coil R is energized. VA compression I spring 126 normally returnsthe switch arm' Dinto contact withthe alarm contact (1 and breaks thecontact C1 as it overcomes the subsiding-e-xpansive forces of thecoolingelement T when the same is de-energized.

From the foregoing it will be seen that when the switch arm D contactswith the contact C a circuit is completed through I the wires L 106, 114and 12 1 to the solenoid 1 $1, the other side of the solenoid beingconnected to L through wire 128. In this man ner the plunger 1? is movedtothe left in Fig.1, disengaging the blades B B B andB from theirrespectivecontacts and i engaging blades 13 ,13 B and B? with therespective contacts C C, C and C". With the control switch blades inthis position as shown in Fig. 1 in" dotted lines, a motor circuit isestablished to rotate the motor armature in a reverse direction to thatwhen the doors 2 were'being opened. This motor circuit may be tracedfrom L wires 106 and 107 toblades B and B From contact C one side of themotor circuit extends through wire 108 to post M ofthe motor M. Fromcontact C 'current is carried by means of conductors 133 and 113 to postM of the motor M. L of the current supply is fed to contacts C and Cthrough the bladesIB and B and the wires 1341:.and 135 to the re versingswitch RS it When this switch is closed by the movementof the rod 130 tothe left Fig. 1 in opening the doors 2, themotor circuit is completedthrough wires 111' and 112to posts M and M respectively of the motor. 7passes through the conductor 137 when the reversing switch BS is closedto engage con tact C energizing the solenoid S which is also connectedto L through the wires136 and 106. Energization of the solenoid 8* re.-vtracts the plungerP whic'h in turn releases the latch shown in Figs. 11and .12. 'This latch, as has been describedabove, normally serves tohold the doors against accidental closing which might result from windor other external forces. I

.When it. is desired'to energize the sole? 7 noi-d S prematurely,thatis, before thesame is actuated by the automatic means describedabove, the operator depresses the push button switch C which will closethe circuit from L throughwire 138? and the solenoid S to L Thus thedoors may be closed at will without waiting for the automatic switch Dto function.

t will'be observed that when the doors 2 are closed the contacts C onone of the doors engage the contacts C on the door frame to" close the.circuit throughv the solenoid S hus the circuit, through this solenoidis broken when the doors 2:begin to open. In

Fig. 11 have illustrated these contacts dia-.

grammaticallyin spaced relation-while in energized is also controlled bythis set screwr By the use of my invention as applied,

for instance, to. fire en inestationswhere, it is essential that the reapparatus" leave the building as quickly as possible uponthe sounding ofa box alarm, the-doors are in the open-position before the fire apparatus is read to leave since it-isonl neces-T sary for the desk man todepress the switch B as he gets the first round of the alarm.

In: this manner the doors .may' often be opened before the first roundis actually completed. My invention provides for automatic closing ofthe doors after a predeter- I mined lapsed period of time,'which maybefrom 15 seconds to 2=or 3 minutes without further attention by the deskman, provided. I

the switch A is left in closed position. If it is, desired'fthatthe-doors remain; open until 70 Part of theicurrent from L? theapparatusreturns from its run,the desk man opens the switch A, but uponagain closing this switch the doors will be closed promptly.

If desired, a manually operated switch (not shown) may be inserted inthe circuit feeding the signal devices A and A, to prevent theirenergization when the doors are opened for purposes other than-to admitor to discharge the fire apparatus. 7

It will be noted that if the sourceof electrical energy at L and Lshould fail for any reason while the doors are in open positlon, thedoors will not begin to close immediately upon the restoration of thecurrent source, but'the closing will be retarded until the coils R and Rheat and the thermostatic element T operates the switch arm D toclosethe circuit through the solenoid S. If the current source shouldfail when the doors are closed and an alarm comes in, the doors may bemanually opened without inenergy; a motor reversing switch in saidcircuitya rodextending along the path of travel of the carriage havingone end oper atively 'connected to said reversing switch; stops onsaidlast named rod and in the path of movement of the carriage whereby saidlast named rod may be operated to reverse the switch when the, carriageapproaches either of its limits of movement.

In testimony whereof I hereunto afiix my signature this 3rd'day ofDecember, 1928.

JOSEPH TL CONWAY.

terference from the door opening mechanism.

tails of construction and arrangement of parts without departing fromthe spirit of the invention or the scope of'the'subj oined claims.

Various changes may be made in the de- 7 ice carriage as it is broughttolrest at either of j its extreme limits of movement on the track, andstops arranged in the path of movement of the rod to engage the endsthereof as the carriage approaches either of its limits of movementalong the track. 2. In an electrically controlled door operatingmechanism; a track;'a carriage capable of travel alongthe track; acushioning device movable with the carriage and including a cylinder, apiston in the cylinder, a rodslidabl-e in the cylinder and fixed to saidpiston, the ends of the rod extending beyond the ends of the cylinder;stops supported along the track and extending into the path of movementof the cylinder and rod for engagement by the rod as the carriageapproaches either of its extreme limits of travel on the trackyrod'sconnecting the carriage with a closure for operating the same as thecarriage travels along the track; an electric motor, an electricalcircuit connecting the motor with a source of electrical

